Washington native Josh Powell, the husband of Susan Powell, who has been missing for two years in Utah, has apparently been killed in an explosion in Graham, WA, along with his two sons, who were on supervised visitation. Authorities say it appears the explosion was deliberate. Powell had moved back to the Puyallup, WA area with his two boys after his wife went missing.

Authorities say it appears the husband of a missing Utah woman deliberately blew up a house, killing himself and his two young sons.

The Child Protective Services worker brought the two boys to Powell’s home, and Powell let his sons inside — but then blocked the social worker from entering, according to fire officials. The social worker called her supervisors to report that she could smell gas, and moments later the home exploded.

Sgt. Ed Troyer, Pierce County sheriff’s spokesman, said emails Powell sent authorities seemed to confirm that Powell planned the deadly blast. The Seattle Times reports that Josh Powell’s lawyer received an email from him shortly before the explosion, saying: “I’m sorry, goodbye.”

According to the Seattle Times, Josh Powell was under investigation in the disappearance of his 28-year-old wife from their West Valley City, Utah, home in December 2009. He claimed he had taken the boys on a midnight excursion in freezing temperatures when she vanished.

— Copyright 2012 The Associated Press with contributions from tamacbsseattle